TST: sql add tests for NaN handling
BLD: catch additional network error messages
API: update nth to use the _set_selection_from_grouper
     makes first == nth(0) and last = = nth(-1)
DOC: groupby v0.14.0 doc changes
Merge pull request #7044 from jreback/groupby_nth

API: update nth to use the _set_selection_from_grouper makes first==nth(0) and last==nth(-1)
BUG: tz info lost by set_index and reindex
DOC: update groupby/v0.14.0 docs for nth
Merge pull request #7092 from sinhrks/appendtz

BUG: tz info lost by set_index and reindex
DOC: groupby.rst edits
DOC: tiny groupby.rst edit
TYPO: idxmax is maximum, not minimum

Confusing doc typo was momentarily confusing.
Merge pull request #7102 from gruen/master

TYPO: idxmax is maximum, not minimum
TST: fixup windows test from GH7092
Merge pull request #7100 from jorisvandenbossche/sql-tests

TST: sql add more tests (NaN handling, ..)
BUG: GroupBy doesnt preserve timezone
Merge pull request #7099 from sinhrks/grouptz

BUG: GroupBy doesn't preserve timezone
BUG: remove unique requirement rom MultiIndex.get_locs to enable
     multi-index slicing on non-unique multi-indexes (GH7106)
Merge pull request #7107 from jreback/mi_slicers

BUG: remove unique requirement rom MultiIndex.get_locs (GH7106)
ENH/BUG: partial string indexing with PeriodIndex
Merge pull request #7043 from sinhrks/pslice

ENH/BUG: partial string indexing with PeriodIndex